1. Technical Field
The present disclosure relates to an electrode strip, a sensor strip and a system thereof, and more particularly, to an electrode strip and a sensor strip having two reactive areas. Notably, there is a time difference between an entrance of the sample liquids into a first reactive area and an entrance of the sample liquids into a second reactive area.
2. Background
Electrodes made by utilizing electrochemical methods can be divided into two types: enzymatic electrodes and non-enzymatic electrodes. At the present time, the majority of electrodes mentioned in technical literature and used in biological substance measuring are enzymatic electrodes, such as well-commercialized blood sugar electrodes. In regard to non-enzymatic electrodes, most of them are used in the testing of general chemical compounds, such as pH electrodes for testing hydrogen ions. Since many enzymatic electrodes have restrictive conditions for moisture preservation, complicated manufacturing processes, and over-elaborate control conditions, manufacturing costs are quite high and mass production is not feasible, and thus, they are only suitable for use by technicians in research organizations and large scale medical testing units.
Relating to the prior art of non-enzymatic electrode strips, such as an electric current non-enzymatic electrode strip disclosed in U.S. Pat. No. 6,258,230 B1, the manufacturing process uses screen printing to spread the reaction layer formulation to cover two electrode systems. The composition of the reaction layer formulation requires large amounts of polymers mixed with a salt buffer. However, an analyte concentration, measured by the above-identified non-enzymatic electrode strips, is usually disrupted by variant hematocrit factors in the blood samples.
The electrochemical method is one of the typical methods for measuring analyte concentrations and involves amperometric responses indicative of the concentration of the analyte. An important limitation of electrochemical methods of measuring the concentration of the analyte in blood is the effect of confounding variables on the diffusion of analyte and the various active ingredients of the reagent. Moreover, the electrochemical method has a problem in that the accuracy of the analyte concentration is disrupted by hematocrit concentrations (a ratio of the volume of packed red blood cells to the total blood volume).
The normal hematocrit range for an average human being is about 35% to about 45%, though in extreme cases, the hematocrit may range from about 20% to about 70%. The mean hematocrit range for a neonatal infant is about 53% to about 69%.
Variations in a volume of red blood cells within blood can cause variations in glucose readings measured by electrochemical sensor strips. Typically, a negative bias (i.e., lower calculated analyte concentration) is observed at high hematocrit levels, while a positive bias (i.e., higher calculated analyte concentration) is observed at low hematocrit levels. At high hematocrit levels, the red blood cells may impede the reaction of enzymes and electrochemical mediators; reduce the rate of chemistry dissolution since there is less plasma volume to solvate the chemical reactants; and slow diffusion of the mediator, causing a lower measured current result. Conversely, low hematocrit is levels can cause a higher measured current result. In addition, the blood sample resistance is also hematocrit dependent, which can affect voltage and/or current measurements.
Additionally, the variation of hematocrit levels is extremely broad, and therefore, needs to be measured by a biosensor and biosensor strips. It is highly crucial to design biosensor strips and a biosensor which effectively prevent hematocrit interference. How to make a system and method to prevent hematocrit interference of an analyte measurement is needed by the present related manufactory.